Quote from: Star One on 01/19/2015 08:12 amPrecisely that was my reading of the situation as well. Not sure where the OP got the idea from that it was shrinking number and would in fact ask them to present some kind of evidence to back up that statement so counter to the actual situation is it.Just an impression, I will candidly admit that. I spoken with several colleagues about that in some occasions and I got the impression that a lot of professional astronomers, if obliged to bet, would now say there is no life at present on Mars (maybe in the past) after some past bandwagon effect.
Precisely that was my reading of the situation as well. Not sure where the OP got the idea from that it was shrinking number and would in fact ask them to present some kind of evidence to back up that statement so counter to the actual situation is it.
Quote from: pagheca on 01/19/2015 09:07 amQuote from: Star One on 01/19/2015 08:12 amPrecisely that was my reading of the situation as well. Not sure where the OP got the idea from that it was shrinking number and would in fact ask them to present some kind of evidence to back up that statement so counter to the actual situation is it.Just an impression, I will candidly admit that. I spoken with several colleagues about that in some occasions and I got the impression that a lot of professional astronomers, if obliged to bet, would now say there is no life at present on Mars (maybe in the past) after some past bandwagon effect.There is the problem perhaps. The issue is no longer one being explored by astronomers but by geobiologists, geochemists, microbiologists, palaeontologists, biochemists.Singular experiences can be misleading as others have said, but currently I am in the field in NZ with a half a dozen astrobiologists, all quite convinced of the possibility of life on Mars either now or in the past. Most are young. So from where I stand it's not a shrinking field.
Quote from: Dalhousie on 01/13/2015 09:01 pmI don't see any impact for the 2020 mission myself, beyond a pointer to the possibility of returning microbial textures.It could, probably should, be used to weight similar lakes but especially playa environments into the landing ellipse (the survey area in that case). Else it will be more a geological than a biological mission again. (It need to be both for biology's sake, but one can always argue the best balance.)I assume it is too late to modify the instrument set (to go through Noffke's microanalysis requirements in situ if possible). Especially since it would be speculative based on tentative findings. That would be more an argument against the pushing of planetary missions against each other so that one can't inform the construction of the next.
I don't see any impact for the 2020 mission myself, beyond a pointer to the possibility of returning microbial textures.
That's interesting to hear & kind of reassuring speaking personally that I hadn't completely misread the situation. The fact we keep finding life on Earth in the most unexpected places even if not directly applicable to the Martian situation must still raises hopes a little.
Singular experiences can be misleading as others have said, but currently I am in the field in NZ with a half a dozen astrobiologists, all quite convinced of the possibility of life on Mars either now or in the past. Most are young. So from where I stand it's not a shrinking field.
Quote from: Dalhousie on 01/19/2015 05:19 pmSingular experiences can be misleading as others have said, but currently I am in the field in NZ with a half a dozen astrobiologists, all quite convinced of the possibility of life on Mars either now or in the past. Most are young. So from where I stand it's not a shrinking field.No problems. I try to feel no attachments to (my) opinions, and I'm very suspicious about "hard" opinions as in the hedgehog and the fox. Actually I found very interesting what you said and would be interested in knowing why they think that, although I think that astronomers have something to say because the attention is now pointed to exoplanets, not only on Mars. Also, note I never said "there is no life on Mars" (others use this kind of hard statement, not me). I just tried to clarify what QuantumG was saying based on my experience.p.s. And I have a very deep attachment to NZ too as I spent a lot of time in the South Island (and got married in Christchurch...). Please let me know where you are. Just curious...
...positions that say "everyone knows there is no life" are really annoying, they are not based on facts and are poor science.
As far as I'm concerned, anyone who takes "what everyone knows" as a set of basic tenets when embarking on scientific research should be dis-embarked. Though those are not as bad as people who undertake research to "prove what I already know is the truth."
Don't take this personally, but just as a general rules: cognitive biases are everywhere. Not only where you (or me) think they are.
Quote from: pagheca on 01/20/2015 02:30 pmDon't take this personally, but just as a general rules: cognitive biases are everywhere. Not only where you (or me) think they are.Oh, not taken personally at all. And I agree with you that, sometimes, radical new theories aren't always the correct new theories. In some cases, it is very true that extraordinary proof is required to support extraordinary theories.And, to toss out the devil's advocacy on it, warm & wet early Mars is becoming "what everyone knows," and to an extent those who theorize that much of the surface evidence we see for ancient liquid water could actually be caused by ejecta and pyroclastic flow events are those who are contradicting the popular wisdom. So, indeed, the biases shift over time (sometimes over very short periods of time), and it is useful to have an aggregate view that cancels out the various biases.I think we can all agree that there is a difference between caution and pig-headedness, though...
Quote from: the_other_Doug on 01/20/2015 04:38 amAs far as I'm concerned, anyone who takes "what everyone knows" as a set of basic tenets when embarking on scientific research should be dis-embarked. Though those are not as bad as people who undertake research to "prove what I already know is the truth."I agree with you but:(1) there is a rationale behind trusting a poll of experts more than a single one or personal judgment, when evidences are not enough: as you probably know it has been demonstrated by a large number of studies that predictions by groups of experts are usually more accurate than anything else. At the conditions those opinions are independent and not the result of bandwagon effect. This works in politics as well as in a SpaceX yearly number of flights poll, for example, that is a good reason to take them quite seriously (and they usually are a quite good predictor...).(2) there is also a complementary mistake: extrapolate from the fact that a certain number of theories were contradicted by new evidences that also the next one will be contradicted soon or later.At the end of the day we all tend to underevaluate the importance of anything that is in contradiction with our current sense of "truth". We should fight this bias and look at evidences, rather than trying to find generic rules to demonstrate this or that. In this case, it is true that Mars maybe (or may have been) a more benign environment to the development of life. However, is also true that there are no indisputable evidences for life on Mars to date, despite our knowledge of the planet increased by several orders of magnitude in the last decade. Don't take this personally, but just as a general rules: cognitive biases are everywhere. Not only where you (or me) think they are.
Quote from: pagheca on 01/20/2015 02:30 pmQuote from: the_other_Doug on 01/20/2015 04:38 amAs far as I'm concerned, anyone who takes "what everyone knows" as a set of basic tenets when embarking on scientific research should be dis-embarked. Though those are not as bad as people who undertake research to "prove what I already know is the truth."I agree with you but:(1) there is a rationale behind trusting a poll of experts more than a single one or personal judgment, when evidences are not enough: as you probably know it has been demonstrated by a large number of studies that predictions by groups of experts are usually more accurate than anything else. At the conditions those opinions are independent and not the result of bandwagon effect. This works in politics as well as in a SpaceX yearly number of flights poll, for example, that is a good reason to take them quite seriously (and they usually are a quite good predictor...).(2) there is also a complementary mistake: extrapolate from the fact that a certain number of theories were contradicted by new evidences that also the next one will be contradicted soon or later.At the end of the day we all tend to underevaluate the importance of anything that is in contradiction with our current sense of "truth". We should fight this bias and look at evidences, rather than trying to find generic rules to demonstrate this or that. In this case, it is true that Mars maybe (or may have been) a more benign environment to the development of life. However, is also true that there are no indisputable evidences for life on Mars to date, despite our knowledge of the planet increased by several orders of magnitude in the last decade. Don't take this personally, but just as a general rules: cognitive biases are everywhere. Not only where you (or me) think they are.There's an old saying, "If it looks like a Duck, smells like a Duck and acts like a Duck, it's probably a Duck... Except when it's not.In other words, while all evidence is pointing towards there being life on Mars, we've been fooled too many times by things that made us THINK we'd found life, but in fact, turned out either as a false positive or inconclusive. So, my guess is, that unless we see something squirming under a microscope, eating and exhaling, no one is going to declare that there is life on Mars. Is it probable that there WAS life on Mars? It certainly looks like there may have been. Is there currently life on Mars now? It's pretty certain that there is no life living on the planetary surface of Mars due to the extremely harsh environmental conditions. Could it survive just below the surface, beneith the dust layer? It's quite possible.but no one is going to stretch their neck out across the chopping block without being darned certain that they've found life. (With our luck, they'll find something, think it's life, and it will turn out to be some sort of microor nanotech robotics from some alien star system and it's a million or more years old).
Those kinds of logic traps are only of interest to philosophers.We've known for decades that there's essentially no life on the surface of Mars. There could be life teaming under the surface, we haven't looked, but the surface is obviously dead.It's kinda like how everyone has accepted there's no liquid water on Mars (and very much related). The only exception we know about is brines so concentrated that they essentially don't count.Why should we care about technicalities?